This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A080369 #7 Apr 04 2015 21:50:42
%S A080369 1,1,6,720,6652800,1693749657600,367216146859161600000,
%T A080369 1888288177044984240734208000000,
%U A080369 4157567140515322460268246337585152000000000
%N A080369 a(n) is the value of Vandermonde determinant for lexicographically earliest n-mark Golomb-ruler.
%F A080369 a(n)=Product[a(i)-a(j)], j<i<=n; product of C[n, 2] positive differences provided by the n marks of ruler.
%e A080369 n=6:the ruler={1,2,5,11,13,18}, the C[6,2]=15 possible differences={17,16,13,7,5,12,11,8,2,10,9,6,4,3,1}; the product = a(6)=1693749657600.
%t A080369 t={marks of ruler}; lt=Length[t] b[x_] := Part[t, x] bd[x_] := Reverse[b[x]-Table[b[j], {j, 1, x-1}]] pb[x_] := Apply[Times, bd[x]] Table[{j, bd[j], pb[j]}, {j, 1, lt}]; vm=Table[Apply[Times, Table[pb[u], {u, 1, k}]], {k, 1, lt}]; Part[vm, lt]
%Y A080369 Cf. A031869-A031875.
%K A080369 nonn
%O A080369 1,3
%A A080369 _Labos Elemer_, Feb 24 2003